FIGS. 1A and 1B are rear and front view diagrams of a conventional crankshaft damper/tone wheel assembly 10. As used herein, “rear view” means a view along a direction of a rotating axis of a crankshaft damper/tone wheel assembly as seen from a side of the assembly that would face an internal combustion engine (not shown) when attached thereto, and “front view” means a view along a direction of the rotating axis of the assembly as seen from a side of the assembly that would face away from an internal combustion engine when attached thereto.
As shown in FIGS. 1A and 1B, a crankshaft damper/tone wheel assembly 10 includes a tone wheel generally shown at 12. The tone wheel 12, also known as a signal wheel, is attached to a crankshaft damper 14, typically comprises a thin circular ferromagnetic plate having an inner opening through which a hub portion 15 of the crankshaft damper is provided. The tone wheel 12 has evenly spaced teeth 16 at its periphery and one or more teeth on a tone wheel are omitted to form an area 18 that permits sensing of angular position of the rotating body relative to a reference point. The tone wheel 12 includes a first surface 12a and a second surface 12b that is raised relative to the first surface 12a. The second surface includes through holes for attaching the tone wheel 12 to the crankshaft damper 14 via fastening members 19. The crankshaft damper 14 is a rotating body attached to the engine crankshaft (not shown) via the hub portion 15. The tone wheel 12 rotates with the crankshaft damper 14 and crankshaft. A tone wheel such as tone wheel 12 can be provided on another type of rotating body, such as a wheel or axle component or other rotating body, along with a magnetic or optical pick up sensor to provide a signal indicating a an angular position of the rotating body or a speed at which the body is rotating.
Many internal combustion engines utilize a tone wheel at a position at a front end of a crankshaft either adjacent to, or attached to a crankshaft damper. Tone wheels used for this purpose typically include a cylindrical portion at the rear side of hub portion 15 (shown in FIG. 1A) that can include a keyway and/or other structure (not shown) for fastening the crankshaft damper/tone wheel assembly 10 to a crankshaft of an internal combustion engine. The hub portion 15 receives a crankshaft end portion and the crankshaft damper/tone wheel assembly 10 secured to a crankshaft.
The crankshaft damper 14 is designed to absorb and dissipate vibration of engine components due to their individual elastic deformations, which result of torsional and axial forces acting on the engine's crankshaft and camshaft from periodic combustion impulses. In FIG. 1B, which shows a front view of the crankshaft damper/tone wheel assembly 10, the damper hub portion 15 is surrounded by a ring-shaped inertial mass portion 20, which is attached to the hub portion 15 via plural spokes 22. A torsionally elastic material 28 is provided between the inertial mass portion 20 and an outer portion of the hub portion 15. However, alternative damping configurations can be used, such as viscous dampers that utilize shear flow from viscous liquid and a ring-shaped weight interacting in a space of a ring shaped housing. The tone wheel 12 is attached to the back of the crankshaft damper such that when the crankshaft damper is attached to a crankshaft, the tone wheel is coaxial with the crankshaft damper and is positioned between the crankshaft damper and the front of the engine. While not shown, the damper can include or have attached thereto one or more pulleys for driving one or auxiliary components (e.g., water pumps, power steering pumps, alternators etc.) using one more belts.